Evaluating Forest Waste on Adsorption of Cd(II) from Aqueous Solution: Equilibrium and Thermodynamic Studies

The aim of this work was to investigate the adsorption potential of Uludag fir (Abies nordmanniana subsp. bornmulleriana Mattf.) on cadmium removal using batch experiments. The effect of parameters such as initial metal concentration, initial pH, biosorbent dosage, stirring speed, contact time and temperature was examined. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms, and the biosorption process followed the Langmuir adsorption isotherms model with high coefficients of correlation at different temperatures. The kinetics of the sorption were analysed using the pseudo first-order and pseudo second-order kinetic models. The pseudo second-order kinetic model fit well in correlation with the experimental results. Moreover, the evaluated thermodynamic parameters (Delta G(0), Delta H-0, Delta S-0) showed that the sorption process was feasible, spontaneous and endothermic in nature. This study showed that Uludag fir (Abies nordmanniana subsp. bornmulleriana Mattf.) can be used as an effective and ecologically friendly biosorbent for removal of Cd(II) from aqueous solutions.